1. Field of the Invention
The present invention is directed to a hub arrangement for a hydrodynamic torque converter including a first hub area with a first connection area for connecting with a converter housing, a second hub area with a second connection area for connecting with a component of a lockup clutch of the torque converter, and a fluid channel arrangement with at least one fluid channel which connects a radial inner area of the hub arrangement with a radial outer area of the hub arrangement and which opens outward in the radial outer area in the direction of a hub rotational axis between the first hub area and the second hub area.
2. Description of the Related Art
A hub arrangement having a first hub area and a second hub area with a fluid channel arrangement connecting a radial inner area to a radial outer area of the hub arrangement is known, for example, from German Reference DE 44 23 640 A1. FIG. 3 of the present application shows a torque converter provided with the known hub arrangement. The known hub arrangement 10' in the above reference comprises a hub component 12' with a bearing pin 14' connected integrally therewith, a first connection area 16' to which a housing cover 18' of a converter housing 20' is welded, and a second connection area 22' to which a carrier component 24' for a clutch piston 26' of a lockup clutch 28' is secured. The clutch piston 26' extends axially in its radial inner area and rests on an outer surface of the second connection area 22' with the intermediary of a sealing ring 30'. Further, a fluid channel arrangement with a plurality of fluid channels extending substantially radially, but at a slight inclination, is formed in the hub component 12'. The fluid channels 32' produce a fluid connection between a fluid chamber 34' formed between the converter housing cover 18' and the clutch piston 26' and--via the different shafts which are shown in the Figure and which are constructed as hollow shafts and especially also the transmission input shaft 40' constructed as a hollow shaft--a fluid source or fluid reservoir. The radial outer side of the space 34' communicates with a space 38' via depressions or grooves formed in friction facings at a clutch plate 42'. The space 38' is substantially enclosed by the piston 26' and an impeller shell 36' of the converter housing 20'. For the sake of completeness, it is noted that the different impeller wheel blades 44', a turbine wheel 46' with a turbine wheel hub 48', and a stator wheel 50', are arranged in the space 38'. The space 38' may also be connected, as desired, with the fluid source or the fluid reservoir via an intermediate space 54' formed between the transmission input shaft 40' and a supporting shaft 52' of the stator wheel 50'. Depending on the chamber (chamber 34' or space 38') into which the fluid is introduced, the fluid pressure will be increased in that chamber in relation to the other chamber and the clutch piston 26' will accordingly be moved either toward the housing cover 18', and therefore in a direction in which the clutch plate 42' is clamped, or in the opposite direction.
In this known torque converter, the hub arrangement 10', as was already mentioned, is formed of one part and is constructed in its different surface regions with configurations for supporting bearings and seal components, for example, of the clutch piston or housing cover. The fluid channels 32' are relatively difficult to produce, which results in complicated and cost-intensive production processes. This is partially caused by the inclined position of the channels. The inclined position of these fluid channels is required to ensure the shown constructional form of the hub arrangement in that the inner openings of the fluid channels in the hub arrangement lie very close to the axis of rotation. This arrangement prevents turbulence induced by the rotating movement to a great extent in the fluid flowing radially inward through the channels in the area of the radial inner openings. Accordingly, it is not possible to construct these fluid channels such that they extend substantially radially, namely, in the area of the hub arrangement formed by approximately annular walls.